Duplex Scanning and Color Flow Imaging of the Lower Extremities

Question 1

3 types of bypass grafts

Answer 1

synthetic graft
reversed saphenous vein graft
in situ vein graft

Question 2

scan the following and obtain PSVs when evaluating a bypass graft

Answer 2

proximal inflow artery
proximal anastomosis
distal anastomosis
distal outflow artery
any sites of stenoses or other noted abnormalities

Question 3

stenotic PSV compared to pre-stenotic PSV

(2:1 ratio) suggests ___
(4:1 ratio) suggests ___

stenotic PSV ≥ 400cm/sec suggests ___

Answer 3

(2:1 ratio) suggests ≥ 50% diameter reduction
(4:1 ratio) suggests ≥ 75% diameter reduction

stenotic PSV ≥ 400cm/sec suggests ≥ 75% diameter reduction

Question 4

significant stenoses and occlusions commonly occur at the level of the ___

Answer 4

adductor canal (Hunter’s canal)

Question 5

the most important element in the assessment of bypass grafts is the ___

Answer 5

comparison of the current study to previous studies

Question 6

when evaluating bypass grafts, look for

a decrease of ___ PSV in any graft segment
a change in ___
a decrease in ABI of ___

Answer 6

a decrease of 30cm/sec PSV in any graft segment
a change in quality/waveform
a decrease in ABI of > 0.15

Question 7

normal vein bypass grafts have

PSVs of ____
lower-resistance flow in the ___

Answer 7

PSVs of > 45cm/sec
lower-resistance flow in the distal graft (outflow artery)

Question 8

abnormal bypass graft findings

PSVs > ___ and velocity ratio > ___
platelet/thrombus formation with PSV > ___
low PSV - assess for ___ or ___

Answer 8

PSVs > 180cm/sec and velocity ratio > 2.5
platelet/thrombus formation with PSV > 300 cm/sec
low PSV - assess for inflow disease or a systemic cause

Question 9

consider revision of LE vein bypass graft if:

focal PSV >
intrastenotic-to-poststenotic SVR >
high ___
interval decrease in ABI >
clinical status changes

Answer 9

focal PSV > 200cm/sec
intrastenotic-to-poststenotic SVR > 3
high outflow resistance (no diastolic flow)
interval decrease in ABI > 0.2
clinical status changes

Question 10

normal stented arteries will likely have elevated ___

Answer 10

elevated PSVs